// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// Thread-safe (provides internal synchronization)

#ifndef STORAGE_LEVELDB_DB_TABLE_CACHE_H_
#define STORAGE_LEVELDB_DB_TABLE_CACHE_H_

#include <cstdint>
#include <string>

#include "db/dbformat.h"
#include "leveldb/cache.h"
#include "leveldb/table.h"
#include "port/port.h"

namespace leveldb {

class Env;

class TableCache {
public:
    TableCache(const std::string& dbname, const Options& options, int entries);

    TableCache(const TableCache&) = delete;
    TableCache& operator=(const TableCache&) = delete;

    ~TableCache();

    // Return an iterator for the specified file number (the correspoinding
    // file length must be exactly "file_size" bytes). If "tableptr" is
    // non-null, also sets "*tableptr" to point to the Table object
    // underlying the returned iterator, or to nullptr if no Table object
    // underlies the returned iterator. The returned "*tableptr" object is owned
    // by the cache and should not be deleted, and is valid for as long as the
    // returned iterator is live.
    Iterator* NewIterator(const ReadOptions& options, uint64_t file_number,
                          uint64_t file_size, Table** tableptr = nullptr);

    // If a seek to internal key "k" in specified file finds an entry,
    // call (*handle_result)(arg, found_key, found_value).
    Status Get(const ReadOptions& options, uint64_t file_number,
               uint64_t file_size, const Slice& k, void* arg,
               void (*handle_result)(void*, const Slice&, const Slice&));

    // Evict any entry for the specified file number
    void Evict(uint64_t file_number);

private:
    Status FindTable(uint64_t file_number, uint64_t file_size, Cache::Handle**);

    Env* const env_;
    const std::string dbname_;
    const Options& options_;
    Cache* cache_;
};

} // namespace leveldb

#endif // STORAGE_LEVELDB_DB_TABLE_CACHE_H_
